Nictitate \Nic"ti*tate\, v. i. [See Nictate.]
To wink; to nictate.
[1913 Webster]
Nictitating membrane (Anat.), a thin membrane, found in
many animals at the inner angle, or beneath the lower lid,
of the eye, and capable of being drawn across the eyeball;
the third eyelid; the haw.
[1913 Webster]